Fluid heating



April 10,1928.

1,666,028 J; E. BELL f FLUID HEATING Filed July L924 14 Sheets-Sheet lINVENTOR l WA'ITORNE J-. BELL- FLUID HEATING. Filed July 1'1, 1924 v4Sheis-Shi 2' INVENTOR 8/ v ATTORNEY,

J. E. BELL FLUID HEATING- I Filed July ,1924

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ATTORNEY \E 3 n o UD QQQDUDDUUQQGUDU April 10, 1928;

J. v E. BELL FLUID HEATING 4 Sheets-Sheet 4 r INVENTOR Filed July 1924Patented Apr. 10, 1928.

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JOHN E. BELL, OF BROOKLYN, NEW YORK, ASSIGNOR -TO FOSTER WHEELERCORPORA- TIONyOF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

FLUID HEATING.

Application filed July 17,1924. Serial No. 726,584.

one side to a source of radiant heat at high temperature, and isconcerned with the mechanical construction and arrangement of suchapparatus, and in particular with the provisions made for accommodatingor re-- straining the tendency of the apparatus to change its form anddimensions as a result of its thermal expansion and contraction.

The invention was primarily designed and especially adapted for use inconnection with steam superheaters composed of elements each formed ofone or more sections with each section several feet in length and havingits walls substantially thicker than ordinary steam pipes having thesame cross sectional area for steam flow. These sections may well beformed of caststeel, and in such case are ordinaril rectangular in crosssection with the out ine of'the element and of the steam channeltherein, each elongated in transverse section in a direction parallel tothe'heat absorbing surface of the element.

When such anelement is put into use, the inner side of the section adacent the source of radiant heat is heated to a temperature appreciablyabove that of the opposite or outer side of the element, and the sidesof the element transverse to the heat absorbing surface arehotter attheir edges adjacent the heat absorbing face than at; theirthe elementto stress if the latterwere free to bend and straighten out inthe mannerdescribed. a p In practice, however, this uniform graduation inthetemperature of themetal of theelement does not exist. The side of theelement remote from the heat absorbing face will be cooler adjacent thesteam channel than at its face remote from the steam channel owing tothe cooling action'of the steam and the fact that the heat which thatside supplies to the steam is received wholly or mainly by conductionthrough the portions of the element which are transverse to the heatabsorbing? face. In consequence, when the element is put into theservice and thereby heated up, the element tends to bend into the formof an arc with its convex side toward 'the source of radiant heat, butthisv bending setsup internal stresses which tend to compress thematerial in the portion of the element adjacent the source of radiantheat and to stretch portions of the element more remote from the sourceofjradiant heat. In the practical use of radiant heat superheaters, thetemperature to which the hotter portion of the element is subjected is agood annealing temperature, while the temperatureof the portion of theelement more re mote from the source of radiant heat-is be v low theannealing temperature.- In Iconseis subjected to a compression stress ityields more or less to this stress and takes a .per-' manent set. Whenthereafter the element cools down, it does not tend to return to itsoriginal straight form, but to bend into the form of an are having itsconcave side toward the source of radiantheat. To some extent thischange in form is cumulative with successive heating up and cooling offofthe element, and the latter will eventually acquire a permanentcurvature when cold with its concave side toward the furnace.

Where the elements are comparatively short, say 4, 5, or 6 feet in'length this ultimate curvature is not ordinarily sufficient to beparticularly objectionable, and I have found that such elements may wellbe so quence, when the hotter side of the element mounted that they arefree to make the changes in form which the changes in temperature tendto produce. With elements of greater length-lmwever, the distortion inthe assembled structures which the temperature changes in theelements-tend'to produce is objectionable and 'should' be restricted orprevented. To this end, I mount the elements in a supporting structureadapted to permit the bodily elongation and contraction of the elements,but effective to limit the otherwise substantial bending movements ofthe elements as they are heated and cooled.

Advantageously in many cases, the supporting framework or structure andthe elements.

are assembled to form aself-contained unit which can be mounted in afurnace wall and which will absorb the stresses due to changes intemperature without transmitting any portion'thereof to the otherportions of the furnace walL. The tendency of a metal such as cast steelto elongate and contract in response to changes in its temperature isnotuncommonly regardedas a'practically irresistible force. 1 have foundhowever, that ,with cast steel elements such as are now being employedin radiant heat superheaters, the tendency of the element to bow intoarc 't'orm asthe result of the temperature changes to which it issubjected, amounts. only to something like 400 pounds per foot of lengtha better understanding of the invention,

however, its advantages and specific objects obtained with itsuse,'reference should be had to the accompanying drawings anddescriptive-matter, in which 1 have illustrated and described some ofthe various forms of construction which may be employed in accordancewith the present invention.

Utrthe drawings:

Fig. 1 isv an elevation partly in section, of

a portion of the wall of the combustion chamber of a boiler furnaceincorporating a rad ant heat superheater;

\ Fig. 2 IS a vertical section taken on the 'line 2-2 of Fig. .1;

Fig. 3- is a plan view partly in section on the line 33 of Fig. 1;

Fig. 4; is an elevation taken similarly to Fig. 1, illustrating amodified construction;

Fig. 5 is a section on the line 5-5 of Fig. 4;.

Fig. 6 is a section on the line 6-'6 of Fig. t;

Fig. 7 isan elevation of a portion of the outer side o1 still anotherform of.combus tion chamber furnace wall superheater;

Fig. 8 is a section on the line 88 of Fig. 7; j i Fig. 9 is a section onthe line 9-9 of Fig. i

Fig. 10 is a partial elevation of a furnace wall supcrheater, comprisingshort elements allowed freedom to bend;

Fig. 11 is a sectionon the line 11--11 of Fig. 10 and Fig. 12 is anelevation of a portion of the outer side of the furnace wall shown inFigs. 10 and 11. 1

lln the drawings, and referring first to the construction shown in Figs.1, 2., and 3,.A. represents the housing wall of a boiler furnace, at therear ofthe combustion chamber a, which is beneath the boiler water tubes1B. Incorporated in the wall A and forming apart thereof, is a radiantheat superheater composed of cast steel elements G, rectangular in crosssection, as shown in Fig. 3.

Each element C is connected at. its ends through transverse and more orless flexible pipe connections D to the steam inlet and outlet headers Eand E, and each element Cis anchored at its center by a suitable connection to a horizontal It beam F. In the particular construction shown,wherein the superheater extends the full width of a boiler furnace oflarge size, the superheater is in ettect divided into two sections, withan'it beam F for each section-the two I beams F being arrangedend to endand each con-- nected at its end adjacent the other to a common verticallt beam Gl fFj'At its end re mote from the I beam G, each ll beam F. is

- connectedto a veptical channel bar H. Each channel bar H is'bonnecttidat its upper and lower ends totlie upper land lower ends of the It beamG channelbars ll. Themembers F, G, H; and it form the main mem.- bers ofa supporting framework for the superheater which is strong enough andrigid enough to hold the superheater elements C against fiexure whenconnected to the latter, as hereinafter described, and which is adaptedto be incorporated in the furnace housin wall and carry the weight ofthe portion thereof above the superheater.

To connect each element C to the K beam F at its rear a yoke-like part 0is welded or otherwise rigidly secured to the rear side of the element.lhe yoke-like part C strad dles, and "is connected by a through pin J tothe tongue J "formed by the adjacent flanges of oppositely facing anglebars riveted to theft beam F. To compensate for the various elements 'Gand yokes C and facilitate assembly, the space in the parts C is of awidth greater than the thickness of the tongue J so that by means ofwashers J on each pin J (shown better in Fig. (i), the correspondingelement C may be vertically adjusted.

At each end each, element C is connected to the'corresponding channelbeam I by provisions which do not interfere with the lonnonuniformity inrelative proportions of gitudinal expansion and contraction of theelement but do prevent movement of the element toward and away from theI beam 1. 'these provisions as shown comprise a tongue-like projection Cwelded or otherwise secured to the end of the elementG and'a verticalpin K by which the tongue C is connected to the side walls of a channelbar K, the base ofwhich is secured against the adjacent flange of the itbeam 1.

Advantageously and as shown, the channel bars K are formed of cast steeland are each 4 of a length equal to the width of some three or four ofthe elementsYC. The space be-- space between the elements C and theinneredges of the frame members F, G, H, and I be apparent that theelements C may elontween the parallel flanges of the channel bars K issufficiently. greater than the. thickness of the tongue projection C topermit the latter to slide along the pin K as required to accommodatethe bodily longitudinal expansion and contraction of the elements C.

In the preferred construction shown, the

is packed with a suitable heat insulating and gas leakage preventingmaterial as Sil-o-Cel, and this material is held in place by coverplates L secured to the members H, J and K.

The bottom horizontal frame members I may rest directly upon thesubjacent masonry portion ofthe wall A, but, onaccount of the necessityfor providing for the longi-' tudinal contraction and expansion of theelements C and the consequent up and down movement of the endconnections, D, I mount the members I, in the construction shown inFigs. 1, 2, and-3, on cast metal pedestals M incorporatedin the housingand each engages some wall, and provide" a space between the subjacentbrickwork portion of the housim wall into which the upper ends of thepedestals M extend and through which the lower end connections D pass.This space is advantageously ,filled with Sil-o-Cel or analogous heatinsulating and gas leakage preventing material, which will yield topermit of the movements of the pipe connections D as the elements Gexpandand contract. As shown,

the outer end of this space is closed by a cover plate 0 formed insections and apertured to receive one or two pipes D. The

sections of the cover plate 0 are held against the outer edge of theSil-o-Cel filled space by angle bars 0 between which the pipeconnections D are clamped. As shown, the angle bars 0 are formed inshort sections two or three of the pipes D.

At the upper end of the superheater, a

space is provided between the upper channel beam I and the brickwork ofthe boiler housing wall above the superheater through which the upperpipe connections 'D pass, and in which they are surrounded by Sil-o- Celor the like as at the-bottom of the superheater. For this purpose, caststeel elements in the form of I bars P are mounted on the top of theupper beams I and support sectional cast steel cover plates P on whichthe brickwork above the superheater is supported. The outer edge of thisspace is closed by parts 0 and 0, similar to those employed at thebottom of the superheater.

The flexibility of the pipe connections D may be sufficient toaccommodate the longitudinal expansion,- and contraction of the elementC when the headers E and E are rigidly mounted. Advantageously. in somecases. however, the headers E and E may be yieldingly supported toreduce the bending gate and shorten as their temperatures increase anddecrease without putting objectionable stress on'any portion of theapparatns, but their tendency to bow in planes parallel to theirlength-and transverse to their heat absorbing surfaces will be preventedby the superheater supporting framework if the latter is strong enoughas it may well be to withstand the tendency of the elements to'bow. Themaintenance of a smooth and comparatively flat heat absorbingsuperheater face is especially desirable to insure the effectiveoperation of thesoot blowing provisions C provided for sweep ing theface of the ,superheater with jets of steam or other cleaning fluid inorder to remove the deposited furnace dust. The super-heater as a wholeforms a self-contained unit which is incorporated in the boiler furnacehousing and the stresses set up in diflerent portions of the superheaterstructure, and such relative movement of the parts thereof as arepermitted, in' response to the changes in temperature to which thesuperheateris subjected, do not react upon or disturb the masonryportions of the boiler housing. i

In Figs. 4, 5, and 6 I have illustrated a construction which isessentially the same in its general features as that shown in Figs. 1,2, and 3, except as to certain specific differences resulting from thefact that the ends by two horizontal channel beams HA.

The connections between the elements C and the beams FA and IA aresimilar'to those between the elements C and the beams F' and I in theconstruction first described. In Figs. 4, 5, and 6, the tendency of theelements to rotate under the action of gravity about the pins K and J isresisted by the end connections D which for this 'purpose are supportedadjacent the elements C by sectional supporting members R formed withhorizontally elongated slots R to per-- mit the bodily elongation andcontraction of the elements C. As shown, the plates R are carried byvertical channel beams'IB alongside the channel beams IA and separatedfrom the latter by a space, which may be together.

filled with Sil-o-Cel to provide a gas tight and-heat insulating packingabout the end connections D, the outer edges of these spaces beingclosed by cover plates'O' and 5, and 6, the elements C are arranged intwo horizontalbanks, the two banks being separated by refractorymaterials which may be supported on the upper element in the lower bank.The possibility of thus holding re-' fractory material incorporated inthe heat absorbing face of the superheater is an ad vantageous one, asit is sometimes desirable to thus reduce the amount of'heat absorbingsurface ofQt-he superheater without corre spondingly reducing the extentof area. of the boiler furnace wall formed b heater as awhole.

The principal formal differences between the construction shown in Figs.7, 8, and 9 and the constructions in Figs. 1 to 6 arises from the factthat in Figs. 7, 8. and 9, the main elements of the supporting frameworkfor the superheater are formed by a multibar FE having its horizontalflange riveted to the horizontal flange of an angle bar FF which in turnis riveted'to thebeams GB.

-o enin F in the vertical fian e of an an le P b c:

Each element C is similarly connected at its,

lower end by angle. bars FE andFF to the beams GB. The openings F in'theangle bars'FE for the-boltscarried by the lugs y the superplicity of lbeams GlB which are parallel to the superheater, the elements C of whichare vertical. The E beams-GB are connected at their ends by channelbeams 1B.

' The intermediate beams GB as shown are arranged in adjacent pairs withthe two beams of each pair spaced away from one another a small distanceand the adjacent beams of adjacent pairs spaced away from one another bya greater distance. The adacent beams of ad acent pa1rs are connected C?are larger than the bolts to accommodate the elongation of the expansionand contraction of the elements G, and are also enlarged horizontally tocompensate for irregularities in the shape and proportions of parts andthereby facilitate assemblage. The bolt or rivet holes F in the anglebars FC may be similarlyelongated for the same purpose as shown. Asshownin Fig. 8 the wall in which the superheater is incorporated forms therear wall of a combustion chamber which extends under the front portions only of the water tubes and which supports the lower edge of abaffle extending across the water tubes. Thisba'tfle is supported (inhollow box-like parts PA of cast metal through which the upper endconnections D pass loosely." The space within the boxes PA around theend connections D, are

packed with Sil-o-Cel or the like, the outer.

ends of these spaces being practically closed bv short horizontal beamsFE and brackets FE about midway between the top and bottom ends of theelements C. The two beams of each pair are alsdconnected by horizontalwebs F18 and brackets F13 In this construction, the elements C areformed in two sections of approximately the same length which areconnected end to end by an internal threaded nipple (3 and also bywelding the adjacent ends of the sections Each element C is anchoredadjacent its center by two connections one to each end of each of thetwo sections of the. elements; The connections for the uppersectionscompriserivets or bolts for securing lugs C welded to thesections to the'-vertical flange of an angle bar FG- having itshorizontal flange riveted to the horizontal flange of a second an le barFD, the latter havingjts vertical ange riveted to the beams GB.Similarly the lugs C at the top of each lower section element.areattached to the vertical flange of an angle bar FC having its horizontalflange riveted to by the super-heater header E which in thisconstruction is connected to the elements 0' by rather short pipeconnections I). The lowerend connections D pass through cover .plates 0which overlap the casing plates .L

andLA between the elements C and their supporting framework.

lln Figs. 10, 11, and 12 I illustrate a construction in which thesup'crheater elements C are comparatively short and are permitted -tobow as well as to elongate and contract in response to the temperaturechanges to which they are subjected. In the particular form illustratedin Figs. 10, 11, and 12 the Jsuperheater is incorporated in the bridgewall AAforming the rear wall of'the combustion chamber proper of aboiler furnace in which the combustion chamber underlies the frontportions only of the boiler tubes B with a baflle 13* extending across.the bank of tubes and resting on the upper edge of the bridge wall.however, that the described construction is not limited to usein thetype of boiler re- It will be 'understood,

ferred to, but may be usedin the outer wall of the combustion chamberunderlying the entire bank of water tubes.

In Figs. 10, 11, and 12 the lower ends of the elements C rest on theportion-of the bridge wall beneath them, and the lower transverse pipeconnections D are restrained against substantial fiexure by supportingmeans which comprises a sleeve U for each lower end connection D throughwhich the latter passes. Each sleeve U is expanded at its ends intoopenings formed for the urpose'in the inner and outer sides of cast ironparts T in the form of boxes open at their tops and each of such length,measured parallel to the length of the bridge wall as to accommodate: aplurality (live as shown) end connections D. The box-like castings.

T may be strengthened by internal ribs orwebs T. The parts T rest oncast metal supports W in the form of, channel bars, and the supports Wand parts T are bedded in suitable cement on the subjacent portion 1 ofthe bridge wall AA proper. The spaces illustrated in Figs.

her

in the parts T surrounding the sleeve D may be surrounded by ganister Aor the like, which forms a support for the masonry portion' A of thebridge wall AA back of the elements Ci 1 v The wall portion A supportsat its top, provisions analogous in'character to those 1, 2,.and 3, and7, '8, and 9 for-permitting the upper end connections D to bend inresponse to the changes in form and 'length'of the superheater elementsas their temperatures vary. Theprovisions shown for this purposecomprise similar castings X and XA having flat top and bottom portionsand vertical web portions X, providing open ended'channels one for theupper endconnection D, the inner end of each of which is received in acorresponding channel of a member XA while an outer portion is receivedin a channel in a mem- X. The castings X and XA are shown as resting oncast supports WA having flanges at their under sides and bedded in asuitable cement on the top of the wall portion.A. Cast metal coverplates Y on the tops of the parts X and XA close the joints between thelatter and directly support tiles A on which the bafiie B rests. Thespacesabout the end connections D within the rear members XA and betweenthose members and the outer members X are packed with Sil-o- Cel or thelike. The upper end connections D are connected into a header EA whichis divided into inlet and outlet portions E and E respectively, by acentral diaphragm E". The lower end connections D are connected into aheader EB closed at each end. This arrangeinentof headers is desirablein some cases as in the particular construction illustrated in which thesuper-heater is composed of elements which are five feet or so long andeiitends the full Width of a combustion chamher which may be twenty feetwide or so, as it'permits the steam admitted to the comp'artment E ofthe header EA to pass first through the elements!) connecting thecompartment E to the header EB and thence through the remaining elementsC- connecting the elements to the oompartmentEA. As shown the header EAand EB are each anchored at one side of the boiler as by means of saddleblocks E and clamping yokes E and at the opposite side of the boiler theend of each header rests upon acorresponding roller support E. g

4 With the construction shown in Figs. 10, 11, and 12, the upper end ofeach element C is free to rise and fall and to incline to the verticalin response to the tendency of the sectional supports for the lower endconnections D'provide sufficient flexibility to avoid objectionablestrains from such stresses as are created by the thermal elongation andcontraction of the'lower header EB. These desirable results are obtainedmoreover with construction and with a minimum tendency to leakagethrough that well. While as previously eXplained,the-repeated heatingand cooling to which the elements 0 of Figs. 10,

11, and 12 are exposed will eventually result in the bending of theelements G into bow form withtheir concave sides toward the combustionchamber X portions as shown,

and whilethis deformation tendency is cumulative -,for a period afterthe super- 'a relatively simple combustion chamber wall heater: is firstput into use, a. stable shape is ultimately attained and in this stablecondition the curvature of the short elements is not excessive, and inparticular is not sutficient to interfere with the efie'ctive operationof the soot blowingprovisions'C.

Aside from prevention of objectionable deformation of the elementsthemselves by restraining'their bowing tendency, there is a specialadvantage inpreventing bending movements'of .the end portions of theelements because of the beneficial effect on the transverse endconnections. When the head ers are rigidly supported, thebodily'elongation and contraction of the elements 0 necessarily resultsin corresponding bending movements of the endconnecting nipples or tubesD. The tendency of such bending movements to work the nipples D loosefrom the elements and the headers .is materially augmented, of course,by the bending movements of'the elements when the last mentionedmovements are not restrained. In

wvith respect to the connections between the same bowing tendency at thesame time. In

elements C and the nipples D, than between the latter and the headers,as it'is more readv plane parallel to its length and transverse ilyfeasible to make a good connection between the headers and nipples Dthan be tween the latter and the elements.

The connection of the elements G closely adjacent their, ends to a rigidsupporting framework, as in the construction shown in Figs'.,l to 9,greatly reduces the diiiiculty of maintaining the strength and tightnessof the joints between the nipples vlD and the elements. Somewhat thesame advantage is secured with the construction shown in lfiigs. 10, 11,and'12 by connecting each element C at each end, and particularly at itsupper end, to the corresponding ends of the other elements as by. meansof an angle: bar F connected to the elements closely adjacent thenipples D, by bolting them to lugs C formed on the backs of theelements. The

advantage of thus connecting the elements C j together adjacent theirends is, largely 'due to the fact that in practical operation thevarious elements are not all subjected to the consequence, thedistortion of an element in which the bowing tendency is relativelylarge, is restricted by its connection to the elements in which thebowing tendency is relatively small. lln practice, the use of the bars Fand particularly of the upper bar F 9, makes it practically possible insome cases to use rigidly mounted headers, where otherwise headersmounted on yielding supports would be required.

Certain features of construction and arrangement pertaining to a-furnacewall superheater having furnace wall lining elements withflexible-transverse end connections extending through the furnace wall,and pertaining to the combination offurs nace wall lining superlieaterelements with a rigid metallic supporting framework not claimed herein,but disclosed in common herein and in my prior application Serial No.607,781, filed December 19, 1922, are

claimed in said prior application.

While in accordance with the provisions of the statutes, ll haveillustrated and dc scribed the best form of my embodiment of myinvention now known to me, it will be apparent to those skilled in theart that changes may be made in-, the form of. the apparatus disclosedwithout departing from the spirit of my invention as set forth in the Icorresponding use ceaoae ment' absorbing radiant heat at one side' whichconsists in substantially restraining the tendency of the element tobend in a 'sists in permitting the element freedom to expand andcontract in the direction of its length while applying force to theelement at points distributed along its length as required to restrainthe tendency of the ele- -ment to bend in a plane parallel to its lengthand transverse to its heat absorbing side.

- 3. In radiant heat absorbing fluid heating apparatus the combinationwith an elongated channeled element absorbing radiant heat at one side,of supporting means, for said element engaging the latter atpointsdistributed along its length and thereby holding the element againstbending movements in a plane parallel to its length and transverse toits heat absorbing side while permittinga bodily elongation andcontraction of the element in the direction of its length. 4 I

i. Radiant heat absorbing fluid heating apparatus comprising a pluralityof elongated channeled elements arranged side by' element whilesubstantially restricting the tendency of the element to bend in a planetransverse to said frame.

5. In radiant heat absorbing fluid heating apparatus the combinationwith a plurality 'of elongated channeled elements. arranged ill) side byside, of a rigid supporting frame to which said elements are connectedadjacent their ends'and at one or more intermediate points by meanspermitting the thermalelongation and contraction of the elements butpreventing movement of the elements at their points of attachment to theframe toward and.away from the latter.

6. Th radiant heat absorbing fluid heating apparatus the combinationwith a plurality of elongated channeled elements arranged side by side,of a rigid supporting frame to which said elements are connectedadjacent their ends and at one or more intermediate points by meanspermitting the thermal elongation and contraction of the elementsbut-preventing movement of the elements at their points of attachment tothe frame toward and away from, the'latten-said frame in planes parallelto their length and transf v verse tothe frame as a whole.

7. In radiant heatabsorbing fluid heating apparatus the combination witha plurality ofelongated channeled elements arranged side by side, of arigid supporting frame to which said elementsfare connected adjacenttheir ends and at one or more intermediate points by means permittingthe thermal elongation andcontraction of the elements but preventingmovement of the elements at their points of attachment tothe frame to- Iward and away from the latter, said fiaine comprising structural'membersparallel to said elen ents'and of a collective longitudinalstifi'ness'suificient to resist without ap- I preciable fiexurethestresses which are created in the elements as their temperatures varyand which tend to bend the elements in planes parallel to their lengthand transverse to the frame as a whole and structural members transverseto the first mentioned members through which the latter are connected tosaid elements.

8. The combination with radiantiheat absorbing fluid heating apparatuscomprising elongated heat absorbing elements and transverse endconnections to said elements, of a furnace wall having metallic partsincorporated therein to form channels through which said end connectionsextend and in. which they are loosely received, and heat insulatingmaterial packed in said channels about the end connections to restrictair leakage through the channels while permit:

ting movements of the end connections re sulting from the thermalexpansion and-con traction ofthe elements.

9. The combination with a radiant heat absorbing fluid heating apparatuscomprising elongated heat. absorbing elements and a 7 mg apparatuscomprlsinga row of elongate ed channelled elements each absorbing .ra-

transverse end connection to one end of each eleinent, of a furnace wallformed -with channels through which said end cdnnec; tions are looselypassed and at the inner side of which said elements are d sposed,- a

header at the opposite'side of the wall to' which one end of eachtransverse connection is connected, means incorporated in the; wall towhich each of said elements is anchored at a distance from itssaid endconnection, and a support for said header adapted to yield toaccommodate the thermalelongation,

and contraction of said elements.

10. The combination with a radiant heat 16th day of July A. D.

absorbing fluid heating apparatus comprismgelongated heat absorbingelements and transverse end connections to said elements,

of a furnace wall having metallic parts incorporated therein to formchannels through which said end connect-ions extend and in which theyare loosely received, and heat insulating material packed in saidchannels about the end connections to restrict air leakage through thechannels while permitting movements of the end connections resultingfrom the thermal expansion and contraction of the elcments and coverssecured to said end connections andclosing the outer ends of saidchannels. 11. In radiant heat absorbing fluid heating apparatus thecombination with a plurality-o'f elongated channeled heat absorbingelements and transverse end connections to said elements, of acombustion chamber wall at one side of which said elements are disposed,a rigid metallic frame incorpor'ated in said wall and metallic portionsat the nels through which said end connections extend-through the walland means anchori'ng said elements to said frame.

12.:A radiant heat absorbing lluid heating apparatus thepombination withelongated, channeled elements provided with transverse end connections,of a furnace wall at one side of which said elements are arranged andwhich is formed with channels through which said connections extend andin which they are loosely received, an an chorage to which said elementsare eonnected at a distance from said end' connections,

a packing of heat insulatingmaterial in said channels abg 'it said endconnections adapted to yield totaccommodate movementssaidmaterialthrough the outer ends ot' said channels.

i 13. In radiant heatabsorbing fluid heatdiant heat-at one side,transverse connections to the ends of the elements for passing the fluidto be heated through the channels element is connected adjacent oneendwhereby the tendency to unequal movements of" the difierentelements.- in response to temperature changes is restricted.

Signed at New Yorkcity, in the county of New York and State of New York,this 1924:. J E. BELL.

in the elements, of a support "to which each

